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Do Diesel Cars And Trucks Save You Money? Not Always

Diesel vehicles get remarkable fuel economy, but it’s sometimes not enough to make them a better value overall than their gas counterparts.

The main reason is the higher pricetag: on average a diesel is $5,045 more than a gas-powered version of the same model, according to Vincentric LLC, a research firm in Bingham Farms, Mich.

Beyond the purchase amount, diesels also end up costing a little extra to own and maintain. That’s partly because some new diesel vehicles are required to have a reservoir of urea, which gets injected into the exhaust and neutralizes some of the pollutants.

With this so-called “clean-diesel” technology, emissions are now cleaner than what comes from many gasoline vehicles—which is a major role reversal. But there is added maintenance involved in replenishing the reservoirs and making sure the more complex diesel engine is running properly.

“We found that diesels typically have slightly higher insurance, repair and maintenance costs,” says David Wurster, president of Vincentric, which specializes in calculating total cost of ownership and chose diesels for its most recent alternative fuel analysis.

“An additional noteworthy point is that on a percentage basis, diesels have lower depreciation, but because they cost more to purchase, their total dollars of depreciation are higher,” Wurster says. (Some might argue that diesel is not technically an alternative fuel, but it’s not exactly mainstream in the United States either, given that only a small fraction of vehicles use it.)

Diesel vs. gas

In a detailed analysis comparing diesel and gas versions of the same models, Vincentric calculated the cost of ownership over five years, assuming 15,000 miles of driving annually. The company found that, in many cases, particularly with trucks and vans, the gas-powered model would end up costing owners less in the long run, despite using more fuel.

But there are enough exceptions to keep anyone who wants to buy a diesel happy.

Vincentric included 23 diesel vehicles in its alternative fuel analysis—which is just about every consumer and commercial diesel currently on sale in the United States. Nine diesels are cost-effective, once all the expenses are tallied, the analysis shows. Eight of those are consumer models.

The diesel that delivers the most significant savings over its gas equivalent is a pricey luxury crossover— the 2012 Mercedes GL350 Bluetec 4Matic. (The “Bluetec” label is Mercedes-speak for diesel, and “4Matic” is its all-wheel drive system.)

Owners will spend $10,128 less over five years on the GL350 than a gas-powered GL450 4Matic, by Vincentric’s calculations. Nearly half of the savings—$4,750—is the result of the GL350 using less fuel, and thus costing less overall at the pump during those five years.

Though filling up with diesel is more expensive—in recent weeks, about 25 cents more per gallon than regular gas, according to the U.S. Energy Information Administration—diesel vehicles like the GL350 get more mileage for the buck.

The GL350’s 19 miles per gallon overall is 27 percent better than the 15 miles per gallon overall that the GL450 gets using gas. So the fuel costs for the diesel work out to less per mile.

2012 Mercedes-Benz S350 Bluetec 4Matic (Credit: Mercedes)

Ranking second on the Vincentric list of cost-effective diesels is a Mercedes luxury sedan. The 2012 Mercedes S350 Bluetec 4Matic will save owners $6,015 compared with a S550, which has a twin-turbo V8 that runs on gasoline, Vincentric says. The savings is mostly on fuel—$4,003.

The S550 is only available with rear-wheel drive, whereas the diesel S350 is only offered with all-wheel drive. This makes the S350’s better fuel economy more remarkable, as driving two wheels instead of four is inherently more efficient. The S350 gets an overall 25 miles per gallon on diesel, an improvement of about 32 percent from the S550’s overall 19 miles per gallon of gas.

Also earning a spot in the rankings are the diesel versions of the AudiAudi A3, the BMW X5, the Ford F-350, and the Volkswagen Touareg. The other Mercedes diesels on the list are the E-Class, the M-Class and the R-Class. (Click here to go to the slideshow and see the full list of diesels that will save you money, ranked according to the amount of savings.)

Ford Tough

The only commercial vehicle to make the cut is the Ford F-350. The heavy-duty, full-size pickup truck is a popular choice for contractors and others who need its hauling and towing brawn.

Of the trucks in Ford’s F-Series, the F-350 is the second most powerful, and its capability makes it costly. Going by the manufacturer’s suggested retail price, the F-350 starts at $30,165, and the diesel engine is a $7,960 option.

But with any vehicle, the retail price is usually just a guideline for negotiations. So Vincentric also factors other data into its equation, such as dealer invoice pricing and consumer rebates. Its intent is to determine what buyers are actually paying.

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I looked at the Vincentric report, and I wonder why anybody would find it reliable. And that’s because no attempt was made to compare vehicles with similar equipment levels. For instance, the Jetta with the $7,111 price premium for the diesel? They compared a base (stripper) gas Jetta to a diesel equipped like the gas powered Jetta SE with convenience package and sunroof. So the $7,111 price premium is reduced by $5,654 – assuming the gas Jetta also comes with rear disk brakes and a trip computer (which it lacks). Corresponding reductions to differences in depreciation, finance and insurance make the diesel Jetta cheaper to own than the gas Jetta. It is also easy to compare the VW Passat SE (gas) – not the cheaper Passat S Vincentric used – to the Passat SE Diesel. The $6,015 diesel premium used as a starting point is significantly overstated; and the legitimate diesel premium again disappears over time.

The cost ownership of diesel vehicles should begin with an apples-to-apples comparison. Otherwise, the results are unreliable and misleading.

Comparing the diesel Jetta to the gas Jetta SE with convenience package and the diesel Passat to the gas Passat SE makes both diesels very close to break-even, based on the criteria Vincentric used (five years of ownership and 15,000 miles driven annually).

So depending on the individual circumstances—for example, some people might keep their cars longer than five years or log more mileage—the diesel models of the Jetta and the Passat could work out to be cost-effective for them.

You make an excellent point about the gas vehicles needing to be a good match for the diesels in terms of trim level—one that both I and Vincentric agree with. Vincentric says it reviewed the choices and updated its analysis accordingly, and the story reflects these recalculated results.

Please bear in mind that the Vincentric analysis is on 2012 models. In some cases, manufacturers have changed the content of their vehicles for the next model year. Thanks for your comment.

Pretty Simple, the cost comparisons above are made by accountants and bean counters. Diesel is the future, next decade anyway…. Ask anyone that is owning them, the performance is there with the economy needed for today’s slow growth America.

I disagree with many for the conclusions and statements made in this article. I have been driving diesel for 15 years both commercially and personally.

Very little emphasis was placed on the fact that the vehicles really get the job done at a break even cost using the skewd math. Don’t forget review experts are not worried about getting the job done.

With the 110 gallons, avg 52-54 MPG that I average each month driving my Jetta TDI 134 miles per working day, I save more in the cost of fuel that I no longer need to buy just to commute to work than I pay on my car note. For anyone that wants a car that can be expected to last 15 – 20 years and more than 400K miles with reasonable care, a diesel is the way to go. As for the additional up front price, you get what you pay for when you purchase. Also, treating a major purchase like a car as a disposable item is poor planning unless you truly have money to burn. I’ve bought three vehicles new and two of them I’ve had for more than 13 years each before retiring them as daily drivers. I’ve learned that if you purchase a quality vehicle and treat it well you can keep a good car almost forever. My 2011 Jetta TDI will save me TWICE its purchase price in 10 years compared with the Ford Ranger 3.0 liter I used as a daily driver for 13 years. As for being more complicated, are you kidding me? A diesel is much less complicated than a hybrid and far less expensive to repair or replace its primary drive train components. Last comment, as for long term value in diesel… just how many Mercedes diesels that are 20, 30 or more years old do you see as daily drivers passing you on the city streets or highway?

My car note costs me $409.58 each month and my fuel savings are in excess of $467.00 each month which also serves to offset a very modest insurance cost increase for driving a car with better overall fuel economy for me (97% highway driving) than a Toyota Prius. I get on average more than 50 MPG each month and more than 700 miles of driving on 13.5 gallons of fuel. My best fuel economy was a combined 58.1 MPG highway/city. My most miles per tank was I think 758 or 765 miles.

The only reasons I waited until 2011 to purchase a diesel passenger vehicle was that until 2011 I never heard about anything in a diesel that had any driving performance (e.g., 80′s Issusu p/u), or that I could afford (MBenz) or anything outside of an F250 or above SuperDuty (again affordability for rec/commute). I finally had to come to grips with my pain at the pump driving 42K miles per year in 2011 when prices went near $5.00/g. I have 52K on my Jetta TDI that I bought in June 2011. It is a great car for the 26K price out the door. I suppose I should also mention my bias. I was a Journeyman Diesel Mechanic when I was a kid in the Navy in the late 80′s – early 90′s. I routinely worked on engines twice my age. I just needed one slightly smaller than my entire car that I could actually drive. After finally buying my Jetta TDI, I learned a VERY disturbing bit of information. The rest of the world has had quality if not AMAZING fuel economy powered by diesel in Austrailia, South America, and Europe. Many of these amazing vehicles being provided by American car mfg’s but not even hinted at in the U.S. when it would have been legal to directly import them for many years I suspect. Enough of my opinion, many thanks for initiating this discussion!

They underrated the VW Jetta. Who can afford a Mercedes? A diesel also lasts, from what I’ve heard anecdotally, a lot longer than a Gas engine. They’re heavier and require different attention, but not excessively so.

The price of diesel in the US is too high. The staggering price for EPA2010 compliant diesel fuel, aimed at the commercial truck industry, is a significant negative for the personal car buyer considering a modern diesel automobile.

Oddly in Europe where their Euro-6 emissions standard is comparable to our EPA2010, diesel is “cheaper” than gasoline. Why is diesel so much more expensive in the US for cars, shich do not cause the road wear that commercial trucks do?

As you probably found in your research, back in the day when diesels dominated luxury-import sales in the United States, say late-1970s-early 1980s, the fact that diesel was cheaper than gas was a big, big factor. And that was when diesels were smelly, smoky and couldn’t get out of their own way! Imagine how modern diesels would do, if fuel taxes were structured to make diesel cheaper than gas once more.

And many of those marbles are still rattling down the road every day. ;->>

I still meet drivers of 240D’s at the pump. Everyone that still has one seems to love the cars.

I don’t know if my Jetta TDI will have nearly as long of a life but the entire car feels so very solid that I can’t imagine it not lasting if I care for the care.

I’m told that it was merely coincidence, that diesel prices went $$$ about the same time the big F250/350 Super Duty and 5th Wheel haulers, diesel RVs came out. That is a little hard for me to believe that there wasn’t some relationship between the two events. I recall back into the 70′s, 80′s how much cheaper diesel was than gasoline.